1923.] Anatomy and Bionomics of Red Colton Bug. 21 
circular in outline (Fig. 8c): a little before it leaves the head 
by the approximation of the splat Into the upper or suction 
canal opens the tip of the pharynx, whilst the lower canal 
receives the efferent salivary duct (S.C. and E.C. Fig. 6b). At 
the base of the maxillary stylet is a curved chitinous rod 
(Mx.L. Fig. 6d) which starting from the maxillary base is at first 
directed towards the pharynx for a little distance, then turned 
back below the base and is finally attached to the head wall 
by a delicate articulation. The apex of the maxillary stylet 
other ornamentation. This stylet is controlled by two series of 
stout powerful muscles. both of which are directly attached to 
its base (Fig. 8), one set, the protractors, run anteriorly and are 
attached to the maxillary Jamina, theother, the retractors, are 
directed backwards and joined to the occipital wall. 
Mandibular Stylets (MN. Fig. 6a, 6b and 6g): They arise 
in the region of the antennae and lie ‘close to the outer sides 
of the maxillary or internal stylets, without any definite arti- 
culation. This stylet also has a swollen base which narrows 
posteriorly; the mandibular protractors being attached to its 
ind mandibular protractors, at one end are attached 
to the inner side of the epicranium and the fulcra, and at the 
other end they are connected to a triangular chitinous piece, the 
mandibular lever (MN. L. Fig. 6a). The latter is connected to 
the base of the mandible by means of a slender chitinous rod. 
The apex of the stylet is acute and pointed. It is ornamented 
with six pacts A directed hooks. 
easurements of the different parts of the head of a 
male individual are as follows :— 
Length of head to the base of the labrum = 1°87 ee 
Breadth of the head in the peer | of the eyes = 1°05 
Length of the ane (Seg: L3 mm., II, 2°25 mm., Tid 
1 mm., IV, 2 m.) =8°75 
Length of the bids m pet fe 
The total length of the inale= 13 mm. 
N.B.—The Individuals were chloroformed and their organs 
measured within 20 minutes after their death. 
The Thorax.—Audouin, as early as 1824, showed that the 
thorax is composed of three similar segments, pro-, meso- and 
metathorax. Each segment is come of four regions: 
